In U.S. Pat. No. 3,419,625, R. C. Doss discloses a method for preparing fluorotrinitromethane. As described in this patent, a solution is formed in a reaction zone by dissolving an alkali metal fluoride in a polar organic solvent. Trinitromethane is then slowly added to the solution while maintaining the solution at a temperature in the range of zero to 100.degree. C., preferably within the range of zero to 30.degree. C. After addition of the tetranitromethane is completed, the reaction mixture is maintained at a temperature within one of the aforementioned ranges for a period of about 0.5 to 100 hours. It is stated that when the temperature has been maintained within the preferred range of zero to 30.degree. C., it is then usually desirable to increase the temperature substantially for a short period of time. While the method described is suitable for preparing fluorotrinitromethane, it appears from the patent that it is only effective in producing the product in low yields. Thus, the maximum yield of fluorotrinitromethane obtained in the runs described in the examples was about 9 percent.
In copending U.S. Pat. application Ser. No. 513,630, filed on Oct. 9, 1974, by one of us, there is disclosed a process whereby fluorotrinitromethane can be prepared in high yields. Broadly speaking, the process comprises the step of reacting tetranitromethane with an adduct of an alkali metal fluoride and a fluorinated or chlorofluorinated acetone in the presence of an aprotic solvent. In carrying out this reaction, an alkali metal nitrite is produced as a by-product. A secondary reaction occurs between the nitrite and the fluorotrinitromethane or tetranitromethane, thereby reducing the conversions and yields. While the process disclosed in the application does produce fluorotrinitromethane in high yields, it would be desirable to eliminate the undesirable by-product so as to obtain even higher yields.
It is an object of this invention, therefore, to provide a process for synthesizing fluorotrinitromethane whereby an undesirable by-product formed during the synthesis is eliminated or substantially reduced.
Another object of the invention is to provide an improvement in a process for preparing fluorotrinitromethane whereby the product yield is increased.
Other objects and advantages of the invention will become apparent to those skilled in the art upon consideration of the accompanying disclosure.